This application claims the priority of 198 16 332.0-16, filed Apr. 4, 1998, the disclosures of which is expressly incorporated by reference herein.
The invention relates to a heating or air-conditioning system for ventilating an occupant compartment of a vehicle, and more particularly, to a system for ventilating several different areas in the occupant compartment.
In a known type of heating or air-conditioning system as disclosed in U.S. Patent Document U.S. Pat. No. 5,016,704, a closing member for controlling the cold-air inlet opening is constructed as a swivellable air flap which, in its one swivelling end position, completely covers the cold-air inlet opening and, in its other swivelling end position, while simultaneously opening up the cold-air inflow opening, completely covers the air inlet surface of the heat exchanger. As the result of a suitable swivelling position of the air flap, the warm-air and cold-air flows flowing into the air mixing chamber can be adjusted such that the mixed air in the distributor chamber has a desired temperature. By way of the various mixed-air outlet openings, this air is distributed to the foot space, the center plane and the head area of the occupant compartment, in which case the air quantities for the individual zones can be apportioned by means of adjusting flaps assigned to the mixed-air outlet openings. In this case, all zones of the vehicle occupant compartment receive air which has the same temperature.
It is important for the vehicle occupant""s well-being to keep the temperature of the temperature-adjusted air flowing into the center plane and the head area lower than the temperature of the air flowing into the foot space. In order to achieve this, it was suggested in earlier German Patent Application 198 04 287.6, to provide an additional cold-air duct which leads into an air duct leading away from the mixed-air outlet opening for the center plane and can be controlled by means of an air flap. By a corresponding opening-up or closing of the air flap, more or less cold air can be added to the mixed air flowing out of the mixed-air chamber, and the temperature of the air flowing into the center plane can thus be lowered to a higher or lower degree in comparison to the temperature of the foot space air.
It is an object of the present invention to implement, in the case of a heating or air-conditioning system of the initially mentioned type, at low technical expenditures, a temperature reduction of the air flowing into the center plane and/or into the head area of the vehicle occupant compartment in contrast to the air reaching the foot space and therefore lower the manufacturing costs of the system.
In the case of a heating or air-conditioning system according to the present invention, this object is achieved by means of a cold air inflow opening that extends over an upper and lower area of a mixed air outlet opening. A two part closing member is provided for the cold air inflow opening. An upper part of the closing member can completely cover an upper dimension area and a lower part of the closing member can completely cover a lower dimension area of the cold air inflow opening. The two parts of the closing member are controlled such that the lower part covers a larger opening cross-section of the cold air inflow opening than the upper part at any position of the closing member.
The heating or air-conditioning system according to the invention has the advantage that, as the result of the division of the closing member for the cold-air inlet opening of the air mixing chamber and the controlling of the closing member parts such that the lower closing member part always covers a larger opening cross-section of the cold-air inlet opening than the upper closing member part, less cold air always enters into the lower area of the air mixing chamber in which the outlet opening for the foot space is arranged than into the upper area of the air mixing chamber in which the outlet opening for the center plane and/or the head area is arranged. As a result, a temperature stratification occurs in the air mixing chamber which has a temperature gradient from the air outlet opening for the foot space to the outlet opening for the center plane and/or the head area. The center plane and/or the head area are always supplied directly from the air mixing chamber with air adjusted to a lower temperature than the foot space. Additional devices, such as a cold-air duct with a control flap, can be eliminated so that the manufacturing expenses are reduced by the elimination of these components.
According to advantageous embodiments of the invention, the two closing member parts can each be driven by a separate adjusting element or can be rigidly synchronized with one another or mechanically coupled. In the former case, the temperature stratification in the air mixing chamber can be individually adjusted; in the latter case, the air stratification is defined according to the concept.
According to a preferred embodiment of the invention, a partition, which divides the cold-air inflow opening, is arranged between the two closing member parts. The partition continues into the air mixing chamber to its rear wall situated opposite the cold-air inflow opening and separates the upper and lower mixed-air outlet openings from one another. Preferably, the partition divides the air mixing chamber only in the area of the two closing flap parts and not completely. By means of this constructive measure, a very good air stratification in the air mixing chamber between the lower and the upper air outlet opening for the foot space and the center plane and/or the head area can be achieved at low technical expenditures.